Immunological and biochemical studies will be performed using monoclonal antibodies F36/22 and M7/105 which recognize determinants expressed maximally on breast carcinomas. The in vivo distribution and molecular profile of these antigens will be determined by analysis against a large panel of normal and tumor tissues. Antibodies F36/22 and M7/105 will be employed in immunohistochemical staining studies in order to phenotypically-classify primary and metastatic breast carcinomas. The immunotherapeutic applicability of these antibodies will be examined in vitro against breast carcinoma cell lines and also in vivo using human tumor-bearing athymic mice. Breast carcinoma antigens will be purified by the use of biochemical fractionation procedures which shall include monoclonal antibody-ligand chromatography. Purified antigen will be used to generate immunoassay procedures for serologic analyses in order to obtain baseline data regarding the value of these tests in diagnostic and patient management applications.